I just stumbled across the following publication that adds additional information to the debate re: whether Gf and g are the same construct, the role of working memory in Gf/g, etc. The abstract for the article is below.

A few of my prior musings regarding this topic can be found by clicking here.

Blari, C. (2004). How similar are fluid cognition and general intelligence? A developmental neuroscience perspective on fluid cognition as an aspect of human cognitive ability

Abstract

This paper considers the relation of fluid cognitive functioning to general intelligence. A neurobiological model differentiating working memory/executive function cognitive processes of the prefrontal cortex from aspects of psychometrically defined general intelligence is presented. Work examining the rise in mean intelligence test performance between normative cohorts, the neuropsychology and neuroscience of cognitive function in typically and atypically developing human populations, and stress, brain development, and corticolimbic connectivity in human and nonhuman animal models is reviewed and found to provide evidence of mechanisms through which early experience affects the development of an aspect of cognition closely related to but distinct from general intelligence. Particular emphasis is placed on the role of emotion in fluid cognition and on research indicating fluid cognitive deficits associated with early hippocampal pathology and with dysregulation of the hypothalamic-pituitary-adrenal axis stress response system. Findings are seen to be consistent with the idea of an independent fluid cognitive construct and to assist with the interpretation of findings from the study of early compensatory education for children facing psychosocial adversity and from behavior genetic research on intelligence. It is concluded that ongoing development of neurobiologically grounded measures of fluid cognitive skills appropriate for young children will play a key role in understanding early mental development and the adaptive success to which it is related, particularly for young children facing social and economic disadvantage. Specifically, in the evaluation of the efficacy of compensatory education efforts such as Head Start and the readiness for school of children from diverse backgrounds it is important to distinguish fluid cognition from psychometrically defined general intelligence.

Recent studies have suggested that the popular earbud headphones (popular with iPods) may produce greater hearing loss than other types. Various narrow CHC hearing-related abilities fall under the CHC domain of Ga.

The most recent studies all appear to be headed the same way - no level of alcohol consumption appears "safe" and the absence of physical features traditionally associated with FAS is a meaningless factor that has become inappropriately focused upon diagnostically when one is assessing cognitive and behavioral disability.

I've admittingly have not paid much attention to contemporary developments in cognitive psychology as per Jean Piaget (esp. since I left SCSU where I taught an introductory develomental psychology class). This is not an intentional slight....it is a casuality of too much information to read. For those with an interest in Piagetian theory and resources, you might want to check out the Piaget Society Web page.

I know that the internet/web has greatly expanded the connections I've recently created and maintained with a broader array of researchers. Interesting reading for those who are interested in the Social Life of Information (this is a great book to read) in scholarly communities.

Thursday, December 22, 2005

Another research study suggesting that "bigger is better" when it comes to brain size. This studyis unique as it is based on brain autopsies.

Intelligence scholars have had a long-standing interest in this research. I've never paid much attention as I don't see much in the way of practical implications...assessment psychologists are NOT going to start measuring the heads of clients.!!!!!!!! The correlations (proportion of IQ variance explained) is of theoretical/statistical significance, but has little practical significance. But....it is interesting cocktail converstation material.

I find it personally interesting given that my brother (and his friends) used to tease me about the size of my head when I was a kid (they thought mine was too big). Now I have ammunition to fight back!!

I just ran a search of my private reference database. All of the records below make some kind of mention of "brain size" in the article...for those who want to know more...happy reading:)

Deary, I. J. (2001). Individual differences in cognition: British contributions over a century. British Journal of Psychology, 92, 217-237.

Garlick, D. (2002). Understanding the nature of the general factor of intelligence: The role of individual differences in neural plasticity as an explanatory mechanism. Psychological Review, 109(1), 116-136.

Yet another research outpost checks in with a research report suggesting that mental time keeping (temporal tracking) may be an important cognitive variable to understand and possibly assess. See my prior musings re: the intriguing recent research on mental time-keeping models and synchronized metronome tapping measurement and intervention.

The current BPS post suggests a link between accuracy of mental time-keeping and a predisposition to boredom.

Wednesday, December 21, 2005

Yipppeeeeee. The CHC listserv membership is now at 798!!!!! Only two more and we will be at 800 and counting!!!! A goal for this next year is to get it over the 1000 mark.

As encouragement, any NASP members who can prove to me (in person at NASP) that they have contributed to the enrollment of mucho members between now and next NASP in March will be awarded a freeCHC listserv shirt (designed by Dr. Joe). I'm bringing 4-5 extras to NASP and plan to give them away at the informal CHC listserv that has been mentioned.

Interesting post over at Cognitive Dailey Blog re: decrement in car driving performance as greater demands are placed on working memory (and multi-tasking) as a function of the difficulty of the conversation in the car. Food for thought.

Interesting post from Google regarding the hot topic Google searches this past year. I'll refrain from making any editorial comments re: any potential meaning about what is important in our culture. Some interesting hit graphs re: news events can be viewed by clicking on the tabs.

Tuesday, December 20, 2005

Another nice post on the Eide Neurolearning Blog re: use of diagramming as a Gv-Imagery (Gv-IM). As per usual, the ENB also provides a link to the original article for those who want to read the original source. Thanks ENB

Interesting article on how Google is being used as a Glr augmentation mechanism. It is very true for me. I'm constantly using Google to find information that I can't recall (or no longer need to stuff into my Glr knowledge net).

Impulsivity/reflectivity is an established cognitive style (Kagan, 1965; Kagan, Moss, & Sigel, 1963) showing two extremes---one of which is denoted as impulsive and the other one reflective. The impulsive style is characterized by fast decisions of which the certainty of being correct is low whereas the reflective style denotes the preference for late decisions associated with a high degree of certainty.

Most clinicians who administer individually administered Gf tests (as part of a comprehensive psychological assessment) often observe that an individual's degree of impulsive or reflective cognitive style can impact Gf test performance. Empirical upport for this clinical observation was reported by Schweizer (2002 - see reference above) who investigated the influence of impulsivity on reasoning in a sample of 108 high school and university students.

Structural equation modeling was applied to predict reasoning by means of an impulsivity composite variable. A path coefficient of -0.33 was reported. This result suggests the interpretation that a high degree of impulsivity impairs performance on reasoning (Gf) tasks. In this study, the -0.33 path coefficient can be interpreted as indicating that for every one standard deviation change in impulsivity (in the direction of increased impulsivity), there was a 1/3 (.33) decrease in measured Gf.

Reasoning (Gf) is a prominent instance of a complex mental activity. Since impulsivity tends to interrupt the execution of well-conceived behavioral plans, it is not surprising to find that an impulsive cognitive style can produce a negative a influence on cognitive tasks (viz., reasoning) where the processing demands are complex.Therefore, a disadvantageous influence of impulsivity on reasoning task performance measures can cause inappropriate responding in completing reasoning tasks (e.g.,. responding exceptionally fast and without a sufficient degree of certainty.

The results of this study support the assumption that impulsivity influences reasoning. As concluded by the authors, this should be regarded as a sort of secondary influence since the reasoning (Gf) ability itself is presumably not impaired. Instead, impulsive people are prevented from performing according to their potential in that at times the concentration on a difficult problem is interrupted.

Friday, December 16, 2005

Over the past few months I've made a number of posts re: synchronized metronome tapping interventions and the potential role of mental time-keeper cognitive models in a wide range of human performance domains.

My two posts this AM regarding the role of musical abilities and language/reading development reminded me (yep....my Glr is in high gear this AM) of a 1997 Annual Review of Psychology article on music which features the importance of mental time-keeper models in understanding music performance.

A few minutes after my earlier post today regarding musical abilities and language development my trusty Glr kicked in. I recalled writing about recent research that has demonstrated a link between musical abilities (Ga-U1, U9, U5) and reading development in young children. Below is the paragraph I wrote which is part of a CHC: Past, Present and Future on-line chapter.

In a welcome contribution to the internal (structural) and external Ga validity literature, Anvari, Trainor, Woodside and Levy (2002) explored the relations between phonological awareness (PC), music perception, and early reading in a sample of 100 four- and five-year old children. Consistent with the above reviewed literature, factor analyses of the four Anvari et al. (2002) PC measures (rhyme generation, oddity, blending, and the Rosner task) revealed a single factor at both age levels. Exploratory analysis of the music tasks (same/different melody, same/different chord, chord analysis, same/different rhythm, and rhythm production tasks) revealed a single music factor for four-year olds and two factors (pitch perception; rhythm perception) for five-year olds. The musical factors appear to measures aspects of the Musical Discrimination and Judgment (U1, U9) and Sound- Frequency Discrimination (U5) reported by Carroll (1993). Moderate factor correlations (.33 to .59) supported the independence of the music perception and PC ability factors. Further support for separate music perception and PC abilities was the intriguing finding that “music perception skill predicts reading even after the variance shared with phonemic awareness is removed. This suggests that phonemic awareness and music perception ability tap some of the same basic auditory and/or cognitive skills needed for reading but that they each also tap unique processing skills” (Anvari et al., 2002, p.127).

Over at Bloglines (the feed service I use to receive automatic updates on posts to my favorite blogs) at site called Cute Overload has been near the top in terms of popular blogs most of this week. Warning...you may overdoes on cuteness.

As usual, another great post on the Eide Neurolearning Blogtoday, this one about the role of music (Ga) in language development (Gc) and reading (Grw).

I recently did a quick literature search on recent empirical articles related to musical abilities and learning and cognition. A copy of the search results (including abstracts) can be found by clicking here.

Wednesday, December 14, 2005

Thanks to the BrainEthics Blog for bringing a new book on "Neuroethics" to the attention of readers/scholars in the neurosciences. Given the almost daily developments in neuroscience research it is important that those working in the field (or those with an intellectual curiousity) address emerging ethical issues.

I've been neglecting my quantoid brother and sisters on this blog...sorry.

As someone who has run many SEM/CFA intelligence models that often include a test of whether two latent factors are unique (latent correlation not equal to 1.0), I found a recent article in the journal Structural Equation Modeling of interest. It is self-explanatory to those who posses QSL (quantoid-as-a-second-language).

I just stumbled across the following article that provides a relatively brief synthesis of 50 years of research on the intelligence of deaf and hard-of-hearing children. I have almost zero knowledge in research in this area....so I cannot judge the quality of the review. This is FYI for those who have an interest and expertise in this area.

McCay, V. (2005). Fifty years of research on the intelligence of deaf and hard-of-hearing children: A review of literature and discussion of implications. Journal of Deaf Studies and Deaf Education, 10(3), 225-231.

In the states there is a spirited discussion regarding the role of traditional cognitive assessment in the identification of learning disabilities. Those who conduct research and practice in the field of neuropsychology typically advocate for the continued use of state-of-the-art cognitive/neuropsychology measures grounded in contemporary research and theory.

For those wanting to get a flavor of this positition, there was a nice and brief overview article recently published in the Journal of Learning Disabilities. Below is the abstract and a link to a copy of the article. Happy reading.

This review surveys the empirical literature for assessments of learning problems in children from a neuropsychological perspective. An evaluation of children with learning problems must consider measures of working memory, attention, executive function, and comprehension (listening and written), particularly for children who do not respond to intervention. These constructs must be tied to intervention techniques, and their connections must be empirically verified. The response-to-intervention (RTI) perspective provides excellent support for the process in young children but is still developing the process for students above the second grade. This review provides information about the existing research on neurobiological correlates of learning disabilities, possible areas for further evaluation, and the link to the RTI movement.

It is clear from listening to the papers presented at the ISIR conference earlier this month (click here for my first "blogging live from ISIR" post...then go forward and read the other posts), as well as a reading of some of the major psychology journals during the past year, that a number of "hot button" substantive topics (viz., Flynn Effect; nature of g; gender and race differences ) have bubbled back to the surface and are enjoying a new round of scholarly study and debate. Kudos to those involved...science must move forward despite potential controversies.

Doug Dettermen, editor of the premiere journal Intelligence, has recently provided an editorial comment on the treatment of controversial intelligence papers. Kudos to Dr. Dettermen for his position.

For the past few years, over on theCHC listerv, I've been making weekly posts called "FYI@IAP - Recent Literature of Interest." The long story short is that I conduct weekly searches of most all social and behavioral sciences journals listed in Current Contents Social Sciences Index. I flag a wide variety of articles that are of interest to me and IAP (beyond just intelligence testing and theories).

Typically I've posted this weekly (and lengthy) list of FYI references to the CHC listserv. I'm now changing this practice.

Starting today (and if my Glr remains adequate and allows me to remember this decision), I'm going to be making these FYI posts via this blog. In addition, I will be posting a copy of each weekly search as a viewable/downloadable pdf file from my web page. For a while I will continue to make FYI posts (with a URL link to the appropriate blog post) to the CHC listserv, but in time, I will stop this practice. So....for those who are routine reviewers of this weekly service via the CHC listserv, you will need to start reading this blog with regularity if you do not want to miss the latest and greatest references this blogmaster flags.

This weeks "recent literature" of interest can be viewed/downloaded by clicking here.

Friday, December 09, 2005

Thanks to all the readers who keep coming back to this humble blog....your patronage is very reinforcing.

Be patient with me this week. I've returned from a week on the road with a heck of a bad winter cold (headache; nasal congestion; sore throat; cough). I'm not operating on all cylinders. But, I shall continue to post as I can and hopefully will be back up to steam in the near future.

Lets here it for the importance of conative (non-cognitive) abilities in understanding and predicting school success. A post over at the BPS blog that showed that sefl-discipline better predicted school success than IQ.

Wednesday, December 07, 2005

Today I receieved a copy of the preliminary conference schedule for the 2006 West Coast Neuropsychology Conference (March 23-26). I believe it is in San Diego. I will post additional information as I receive it.

Monday, December 05, 2005

A number of unrelated research data points that have come across my inbox (cortex) during the past few weeks have suggested, at least to my quirky cortex, the there may be something important happening regarding our understanding of the ability to improve mental performance as a function of neural plasticity. In particular, within the past few weeks I've made posts (with links to research) re:

While at ISIR I was sent a pre-publication copy of an interesting article by Stankov and his colleagues (Stankov was the first psychometric/intelligence researcher to posit a temporal tracking ability) that seems related. The article (click here to view) reported the relationship between brain phase syncrhonization and CHC abilities. I couldn't help but see a possible common thread across all these data points.....namely, the relationship between cognitive abilities and brain synchronization/tuning.

I need to cogitate on this stuff more. These data points are indeed interesting. What are the implications for assessment? What are the implications for possible cognitive/achievement interventions. My somewhat synchronized brain wants to know.

There was an article in the Wall Street Journal this past week regarding the neural plasticity in old age. I couldn't find a link to the original article online, but with the help of a friend, was able to get an e-copy of the text which I have pdf'd for viewing by clicking here

Sunday, December 04, 2005

I ran across a nice "15 minute intro to blogging" while sitting in the Mpls airport just now. If you want to better understand what blogging is all about, with examples from education, check out the link to "Thinking Outloud"

ISIR 2005 is over. A damn good conference. For those interested in research and theory in intelligence, this is THE premiere conference. Also, it is very unique as it is a small fraternity/sorority of scholars who have been talking, disagreeing, etc for decades. The conference typically has around 50 in attendance, which results in a program where everyone watches and discusses every presentation in a single room. This results in a very rich and deep level of intellectual interchange and a very open and comfortable atmosphere, even for those of us who feel like we are simply lucky to be in the same room with these giants (Hunt, Gottfredson, Widaman, Bouchard, Lubinksi, etc.).

I look forward with great anticipation to next years conference in San Francisco. Finally, kudos to Doug Detterman and his students for coordinating yet another great meeting.

Reynolds & Keith. A test of Spearman’s law of diminishing returns in the Kauffman Assessment Battery for Children, Second Edition.

From Program Abstract

According to Spearman’s “law of diminishing returns,” positive correlations among cognitive ability tests are higher in low ability groups versus high ability groups. Raw data from the Kaufman Assessment Battery for Children, Second Edition standardization sample were studied to determine if the phenomenon is present in this intelligence battery. The sample used in this study included 2175 participants ranging from 7 to 18 years in age. The sample was split into two groups: One group included individuals who had a Fluid-Crystallized Index (FCI) of 100 or below (low IQ group) and a second group included those who had a FCI of above 100 (high IQ group). The FCI is comparable to a Full Scale IQ score.

Principal component analyses were used to replicate a previous study of the Wechsler Intelligence Scale for Children, Revised (Jensen, 2003). Confirmatory factor analyses using nested factor models were used to answer questions related to the changes in factor variances, subtest loadings on the g factor, and intercorrelations among broad ability factors. Results from the PCAs indicated that the law of diminishing returns was present in the KABC-II, although it was not produced uniformly across the subtests. Results from the CFAs indicated that higher g is associated with lower g variance, a depression of subtests’ g loadings, and lower intercorrelations between the broad ability factors. The law of diminishing returns was present in the KABC-II: g appears less general and more differentiated in a high IQ group compared to a low IQ group. This phenomenon was not produced uniformly across subtests, but it was also not produced only by the subtests with the weakest g loadings.

There has been an extensive debate concerning the nature, causes, and implications of the secular increase of scores on cognitive ability tests (i.e., the Flynn Effect). The aim of this study is to compare the scores on unaltered subtests across the US standardization samples of the Woodcock-Johnson (WJ; Woodcock & Johnson, 1977), the Woodcock-Johnson-R (WJ-R; Woodcock & Johnson, 1989) and the Woodcock-Johnson-III (WJ-III; Woodcock, McGrew, & Mather, 2001). Structural equation modeling with mean structure is employed to shed light on the precise nature of the trend in scores on both the cognitive ability and achievement tests. In addition, with tests of measurement invariance (i.e., the absence of measurement bias) with respect to cohorts and periods, it is investigated whether score gains could be attributed to latent increases in ability or to measurement artifacts such as heightened test sophistication. Moreover, we consider trends over time with age held constant (e.g., 30-40 year-olds in 1976 vs. 2000), as well as differences between cohorts (e.g., those born in the 1950s vs. those born in the 1960s). Disentangling cohort effects from time-of-measurement effects may contribute to our understanding of the Flynn Effect, because the causes of these two types of effects are different. For instance, hypotheses concerning the effects of nutrition, family size, and heterosis are related only to cohorts, whereas most hypotheses concerning test artifacts are related to time-of-measurement.

Recent research by presentor has suggested that Flynn effect is more subtest (individual test) specific...and may be reflecting changes in specific/narrow abilites (test specificity) over time.

WJR/WJ III findings/comments

Advantage over prior research is use of contemporary CHC theory

Preliminary findings.....only on subset of cognitive tests. More will be analyzed later.

Used common items across editions. Rasch equated scales provided common metric across editions.

Author suggests 4 possible level sources of gain/change that need to be investigated (and which he is investigating): g, broad abilities, test specific abilities (Spearman's "s"), DIF/item drift. Presentor criticizes Flynn for dumping all these sources together....ignoring them. Presentor is using multiple group confirmatory factor analysis (MGCFA) in current research.

Presentor is using demographic variables from both editions to re-weight norm samples to control for sampling differences across time.

General findings.

MGCFA to investigate the 4 level sources above. Concluded -- way to much to summarize. I need to listen...sorry. Wicherts research results will be interesting and need to be monitored by serious intelligence scholars.

Flynn effect not present in children and adolescents (Flynn effect over?) but present in adult samples.

Mean difference changes (over time) are related to g and some due to changes in subtest specific/narrow and broad abilities.

This study examined the Lynn-Flynn Effect (LFE) using data from the Mathematics section of the College Basic Academic Subjects Examination (Osterlind, & Merz, 1990) from 1996 to 2001. This study used Item Response Theory (IRT) methods to assess the magnitude of change in cognitive abilities, because, as Beaujean (2005) showed, under certain conditions, score comparison methods derived from Classical Test Theory (CTT) are unable to distinguish between real rises in cognitive abilities (Lynn, 1989) and mere psychometric artifacts (Burt, 1952; Brand, 1989)---a limitation IRT comparison methods were able to overcome. This study found a trend similar to that of Sundet, Barlaug, and Torjussen (2004) and Teasdale and Owen (in press), namely a dysgenic effect since the mid-1990s.

Live presentor comments

IRT can help ascertain true differences in abilities over time which can be confounded by changes in item difficulties over time (in CTT).

IRT can be used to equate item difficulties on a common scale across test editions--to allow generation of ability estimates, across test editons, on a common ability (latent trait) scale.

Friday, December 02, 2005

The reality of live blogging caught up with me today. I started off with good intentions here at the ISIR conference. I had written a considerable amount on a bunch of papers presented during an intelligence/gender difference symposium and the wifi signal from the hotel kept dying. Whenever it died, when I reconnected, I often found the text I had written as unuseable. I encountered a bunch of "html code" errors when I tried to save and post. After reconstructing everything from scratch a third time, and again having the same problem, I capitulated.

Lesson learned. Wifi live blogging has a large error term. A direct connection would seem to be desirable. I've not decided if I will try again tomorrow during the last day of the conference. We shall see.

Damn...no sooner than I post a link to information that suggests that coffee can be good for you (this morning) and another study is reported (Science Blog) that deals with the darker side of caffeine addiction......and its possible genetic relation to alchohol addiction.

Fagan, Holland & Wheller. The prediction from infancy, of adult IQ and achievement.

Program Abstract

A sample of 66 young adults (18 to 24 years old), who were originally tested at 6 to 12 months of age on the Fagan Test of Infant Intelligence (FTII) for their ability to recognize briefly presented photos of previously unfamiliar faces were recently revisited. A current estimate of IQ was obtained from each. A measure of achievement was derived by computing the ratio of years of education attained divided by current age. The intellectual functioning of the sample at 21.9 years, (SD 1.3 years) was in the average range with a mean IQ of 106.7 (SD 14.4). The average educational level achieved was 14.2 years (SD 2.2). Information processing ability estimated during the first 6-12 months of life was predictive of adult IQ (r = .34 p < .006) and of academic achievement (r = .25 p < .05). Corrected for unreliability, these coefficients are r = .59 and r = .44, respectively. The present results support earlier studies indicating the continuity of intelligence from infancy and illustrate the validity of basic measures of information processing for the long-term prediction of achievement.

Comment. Although correlations reportedare statistically significant, and important for theory building and research, they fall far short of the magnitude necessary to make any reasonable predictions regarding any particular individual.

Widaman. Factorial invariance and the representation of within-groups and between-groups differences: A reconsideration

Finally, a presentation for the quantoids in the audience (including Tim Keith and author of that hot new book on multiple regression--Multiple Regression and Beyond)! I've always made it a point to read most all of Keith Widaman's SEM/CFA writings.......both methodological and substantive.

Quick decision - this presentation is too complicated for me to track and summarize live (PPT slides with matrix algebra - my "matrix-algebra-as-a-second-language" abilities have decayed since graduate school). Below is the program abstact. Link to Widaman's web page is above. Link to article he is refuting is embedded in the abstract below.

Program Abstract

In a recent paper in Intelligence, Lubke, Dolan, Kelderman, and Mellenbergh (2003) argued that factorial invariance had implications for the study of within-group and between-group differences. Lubke et al. identified several levels of factorial invariance, the most restrictive being strict factorial invariance in which factor loadings, manifest variable intercepts, and unique factor variances are invariant across groups. Lubke et al. argued that a finding of strict factorial invariance implies, at a mathematical level, that the sources of within-group differences are identical to the sources of between-group differences. Several implications of this claim were drawn, such as the claim that a finding of high heritability of within-group differences (i.e., within-group differences are due primarily to differences in genetic endowment) implies that between-group differences are also due to genetic sources of variance. In 1974, Lewontin posed a thought experiment in which between-group differences were due to completely different sources than within-group differences. Lubke et al. argued that data consistent with the Lewontin thought experiment would lead to a rejection of strict factorial invariance if a model were fit to such data.

The core of the present presentation is to dispute the central conclusion offered by Lubke et al. The most important issue is the relation between levels of factorial invariance and the claim that strict invariance implies that between-group and within-group differences are due to the same underlying causes. First, the multiple-group confirmatory factor model will be described, together with increasing levels of factorial invariance (configural, weak, strong, and strict). Then, the central conclusion by Lubke et al. will be described as being due either to a linguistic error or to an error in conceiving the relation between parameters and sources of variance in hypothetical examples Lubke et al. considered. If strict factorial invariance holds, then the latent variables underlying the manifest variables are responsible for (a) within-group differences on the manifest variables, and (b) between-group differences in mean and variance on the manifest variables. Therefore, the latent variables, or factors, are mathematical entities that represent or embody all information about within- and between-group differences on the manifest variables. However, these latent factors can be combinations of genetic and environmental variance, and different combinations of genetic and environmental sources of variance can influence within- and between-group differences on the manifest variables.Two simulated data sets designed to embody competing hypotheses for the Lewontin thought experiment will be described. In one data set, the sources of within-group differences are also responsible for between-group differences; in the second data set, the sources of within-group differences explain none of the between-group differences. Consideration of these data sets leads to the formulation of rules for study design that will enable a test of the hypothesis that sources of within-group differences are also responsible for between-group differences. The implications of these findings for research on intelligence are then explicated.

This is day 2 from ISIR. Posts will be less frequent, primarily because the second half of the day is going to be hosted at the "Mind Institute" away from the conference hotel. I doubt I will have wifi access. The PM symposium is on brain imaging studies. I might try to take notes and post later.

As I am sitting here in a hotel room in Albuquerque, NM drinking my morning coffee, I was pleased to discover a post over at Mind Hacks re: a study that suggests that coffee may have a positive effect on the frontal cortex (and executive functioning).

Thursday, December 01, 2005

An interesting quote at the ISIR conference...source unkown. "In most sciences there is recognition that most accomplishments occur by standing on the shoulders of giants [this comes from Merton]---but---in psychology we tend to stand on our predecessors faces." :)

Yes...more evolutionary psychology stuff and intelligence. That is the theme of all papers today. More practical papers come the next two days. Stay tunned. Remember, I'm more-or-less just regurgitating what is presented...not endorsing it.....this (evolutionary psychology) is NOT my area of expertise.Miller. Mutual mate choice for intelligence as a fitness indicator.

I had a hard time focusing after lunch, so my comments for this paper are more haphazard and ADHD-driven.

The three major models advanced to explain the evolution of human intelligence:

Survivalists models - those who developed better tools dominated and survived. Bigger brains did better.

Social intelligence models - More clever brains can manipulate less clever brains...and thus, the clever brains survive and evolve.

The presentor has devloped an algorithm (go figure) called the "fitness matching model." Not enough time/space here to describe. If you want more information, check out his book. Also check out some independent comments on his work.

Geary. The Origin of Mind: Evolution of Brain, Cognition, and General Intelligence.

The gist of Geary's presentation is the explanation of human brain (intelligence) evolution via three classes of pressures. As summarized in much of the evolutionary psych literature are the classes of climactic and biological pressures. Beyond these, Geary focused primarily on social pressures....which are breifly summarized below. I think I'm going to put Geary's book on my holiday wish gift list.

Social pressures - Ecological dominance--that is, controlling the environments where the climactic and biological pressures operate. A struggle with other people for control of the ecologies. According to Geary, "the primary dynamic that has driven and is currently driving human evolution is competition with other people and groups of other people for resource control (e.g., of other people, food, and land)...social competition results in variability in social dynamics and through this creates pressures for the elaboration of systems of brain and mind that can anticipate, mentally represent, and devise behavioral strategies to cope with these complex social dynamics."

"These systems create self-centered mental models that enable the simulation of the ‘perfect world’, a world in which other people behave in ways consistent with one’s best interest, and biological and physical resources are under one’s control: These mental models enable people to devise behavioral strategies to cope with the actions of others and to better compete with others for social influence and resource control. The systems that evolved to support the use of mental models are known as general fluid intelligence (Gf), working memory (Gsm-MW), and attentional control (executive function) [Note....CHC info in parentheses added by me...the blogmaster]. The combination of these systems...is the foundation upon which human intellectual and cultural advances have been built.

According to Geary, our primate ancestors could not engage in the ability to imagine this "perfect world"....thus, explaining, in part, why the human brain incrementally evolved. Gf, working memory, and attentional control, which seem to be located primarily in the prefrontal cortex, are hypothesized to have allowed humans to do "future thinking", "mental simulations", "self-awareness", etc. For those who could do it well, this resulted in ecological dominance. These individuals had a better chance of survival and passing on their genes and in turn, the evolution of higher and higher Gf, working memory, etc.

Interesting article on the Science Blog re: the coordination of brain regions via "tuning." Now...a key question is what interventions/treatments can help us better "tune" our brains to increase efficient performance.

More potentially controversial research to share around the water cooler.

Prokosch. Intelligence and Mate Choice

"The role that intelligence plays in human mate choice was examined. A large amount of research indicates that intelligence is an important criterion when selecting for a potential partner, and this preference varies both between sexes, with women valuing it more than men, and according to which mating strategy, long-term vs. short-term, one adopts. The question that remains to be answered is why such a preference has evolved. Most research has assumed that intelligence functions to indicate direct parental investment and resource acquisition, especially in males. However, there is also a possibility that intelligence functions to indicate indirect “good genes” benefits apart from any direct payoffs. In order to assess the plausibility of both mechanisms, this study examined five empirical questions:"

The presentor attempted to answer the following questions via the following research design.

Three groups of 5 males were selected for female evaluation (mean age =19; college students). Males were ordered on a measure of Gc (WAIS-III Vocabulary). 204 normal ovulating woman randomly viewed (3 minute videos) and rated each male (controlled for physical attraction). Male behavioral data was collected using video-recordings, and women then made various assessments based on relative male performance. Menstrual cycle data and objective intelligence measures were also collected.

1) How accurate are women at assessing intelligence given only brief exposure?

In general, they were accurate (significant linear trend).

2) How important is intelligence in a potential long-term mate?

Males that were brighter were viewed more positively as a potential long-term mate.

3) How important is intelligence in a short-term mate?

Same as conclusion in # 2. But physical attractiveness was a strong predictor in a short-term context. In addition, when a "creativity" variable was entered, it was more important than Gc (with an interaction with female intelligence -- brighter females preferred creativity more, than lower ability females,in a short-term context)

4) Does female conception risk influence either the accuracy of assessing intelligence or the preference for intelligence?

Nope. Probability of conception (a function of woman's cycle) was not related to accuracy of perception of intelligence and/or preference for higher intelligence in long- and short-term contexts. However, there was a significant short/long-term context by probabilty of conception (time during menstral cycle) interaction----greater preference for creativity in a short-term context.

5) Does the degree of female intelligence influence the accuracy of assessing intelligence or the preference for intelligence?

Nope...no significant relationship found.

Hmmmmm....I'm not going to suggest any practical implications what-so-over.....this is too potentially controversial. But again, much of the evolutionary psychology research can be great for cocktail conversations.

Again....a paper with not much immediate practical value...except maybe for generating interesting cocktail trivia conversations. "In press" copy of the paper is available at Dr. Gottfredson's web page.

Gottfredson. Innovation, Fatal Accidents, and the Evolution of General Intelligence

Paper Abstract

Since the 1970s, most evolutionary psychologists have conceptualized human intelligence as an aggregation of many independent, highly specific problem-solving modules, much like a Swiss army knife (Tooby & Cosmides, 1992). Some now cite the evidence for a g factor to argue that human intelligence is domain general. Their favored explanation for its evolution is that runaway selection for the ability to manipulate conspecifics was unleashed within groups when humans gained mastery over their external environment (“ecological dominance”; e.g., Geary, 2005). However, their explanadum is actually a postulated social or Machiavellian intelligence, which leaves g unexplained. I compile evidence from psychometrics, job analysis, personnel selection, accident analysis, and hunter-gatherer societies to show how external ecological forces could, in fact, have selected for g during the last half million years and also accelerated its selection after Homo sapiens emerged about 150,000 years ago.

The following facts illustrate one such mechanism that could have selected for higher g: (1) fatal accidents (unintentional injuries) are a major cause of death in all societies, including the most technologically primitive (e.g., the Ache, !Kung), (2) fatal accidents disproportionately kill reproductive-age individuals, usually males while engaged in provisioning-related activities, (3) preventing accidents and limiting the injury they cause is highly g loaded, (4) hazards are ubiquituous in daily life, myriad in kind, and low-probability killers, so they tax attentional resources while tempting neglect, and (5) the fruits of provisioning competence are widely shared within human groups, but provisioning-related injuries are not. Daily life’s myriad hazards are like lightly g-loaded items on a very long mental test for avoiding accidental death: no single one matters much, but they cumulate over time and individuals to disproportionately cull the lower-g members of a group.

Most hazards are evolutionarily novel because they are by-products of human innovations. While innovations lowered absolute rates of mortality, the new hazards increased g-related relative risk of death from unintentional injury. Rate of selection for g could have accelerated (i.e., g-related relative risk of death increased) when humans began flooding their EEA with innovations (fire for cooking and hunting, weapons, tools, rafts, etc.) whose hazards could exceed the limits of normal human tolerance (crushing, piercing, poisoning, drowning, brain trauma, etc.). I describe specific mechanisms that could have accelerated selection for g since the speciation of Homo sapiens: double jeopardy, the Spearman-Brown pump, spiraling complexity, contagion of error, and the migration ratchet. The general thesis is that the most powerful ecological forces selecting for g were not the joint threats to survival that riveted the attention of early human groups (starvation, warfare, etc.), but the relentless parade of less obvious, less compelling threats to the survival of individuals, one by one.

Presentor aruged that human "innovation" was the primary variable that influenced the probability of accidents and subsequent evolution of general intelligence. For example, more innovations-->more complexity-->more hazards-->bigger consequences (accidents and risk)-----results in more "pruning" of low end of g distribution. That is.....brighter people in populations increase innovation, that via the sequence above, results in greater risk of accidents and deaths for the entire population, which, because of their lower g, results in greater death among those low in intelligence....thus resulting in general increase in g over time.

Hmmmm. Brighter people make life more risky for the rest of the population?

About Me

Dr. Kevin McGrew is Director of the Institute for Applied Psychometrics (llc). Additional information, including potential conflicts of interest resulting from commercial test development or other consultation, can be found at The MindHub(TM; http://www.themindhub.com ). General email contact is iap@earthlink.net.